Q. A technique based on inter-sub band transition is known as ___________

View solution

Q. In a QC laser, a same electron can emit number of photons.

View solution

Q. The phenomenon resulting in the electrons to jump from one state to another each time emitting of photon is known as ___________

View solution

Q. A QC laser is sometimes referred as ___________

View solution

Q. In QC lasers, it is possible to obtain different output signal wavelengths. This can be achieved by ___________

View solution

Q. QC lasers ______________ the performance characteristics.

View solution

Q. An MQW cascaded laser is more advantageous because of ___________

View solution

Q. The absence of _______________ in LEDs limits the internal quantum efficiency.

View solution

Q. The excess density of electrons Δn and holes Δpin an LED is ____________

View solution

Q. The hole concentration in extrinsic materials is _________ electron concentration.

View solution

Q. The carrier recombination lifetime becomes majority or injected carrier lifetime.

View solution

Q. In a junction diode, an equilibrium condition occurs when ____________

View solution

Q. Determine the total carrier recombination lifetime of a double heterojunction LED where the radioactive and nonradioactive recombination lifetime of minority carriers in active region are 70 ns and 100 ns respectively.

View solution

Q. Determine the internal quantum efficiency generated within a device when it has a radiative recombination lifetime of 80 ns and total carrier recombination lifetime of 40 ns.

View solution

Q. Compute power internally generated within a double-heterojunction LED if it has internal quantum efficiency of 64.5 % and drive current of 40 mA with a peak emission wavelength of 0.82 μm.

View solution

Q. The Lambertian intensity distribution __________ the external power efficiency by some percent.

View solution

Q. A planar LED fabricated from GaAs has a refractive index of 2.5. Compute the optical power emitted when transmission factor is 0.68.

View solution

Q. A planar LED is fabricated from GaAs is having a optical power emitted is 0.018% of optical power generated internally which is 0.018% of optical power generated internally which is 0.6 P. Determine external power efficiency.

View solution

Q. For a GaAs LED, the coupling efficiency is 0.05. Compute the optical loss in decibels.

View solution

Q. In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10⁻⁴ Pint)

View solution